Thyroid Disorders. A brief guide to everything you need to know

By Dr. Girish Parmar in Endocrinology

Apr 24 , 2023 | 3 min read

What is thyroid gland?

It’s a butterfly-shaped endocrine organ located in the midline of the neck, in front of the windpipe (trachea) and below the Adam’s apple.

What is the function of the thyroid gland?

It takes the iodine present in foods and uses it to manufacture two hormones primarily – T4 and T3. These hormones are then released in the blood and circulate throughout the body.

What is the function of thyroid hormones?

T4 and T3 hormones control the body’s metabolic rate (i.e. the speed at which the body cells work), body heat, and the energy levels of an individual.

How is the thyroid gland controlled?

The production of T4 and T3 by the thyroid gland is controlled by the ‘master endocrine gland’, known as the pituitary gland. The pituitary gland is a part of the brain and is located between the eyes. It is about two inches in size.

The pituitary gland produces a hormone called TSH (Thyroid Stimulating Hormone) which, as the names suggests, stimulates the thyroid gland to produce T4 and T3.

Once these hormones have reached the upper limit of what is considered normal, they inhibit further production of TSH (i.e. T4 and T3 have an inverse correlation with TSH).

How is the thyroid function measured?

Estimation of the blood levels of T4, T3, and TSH, establishes the functioning of the thyroid gland. These tests can be done at any time during the day and fasting isn’t required.

What are the disorders of the thyroid gland?

Thyroid gland disorders can be of 2 types:

  • Underactive thyroid gland, also known as Hypothyroidism
  • Overactive thyroid gland, also known as Hyperthyroidism


Hypothyroid (Underactive Gland) Hyperthyroid (Overactive Gland)
Underactive thyroid gland Overactive thyroid gland
Decreased production of T4 and T3 Increased production of T3 and T4
Decreased metabolism Increased metabolism
Symptoms Symptoms
Decreased heart rate Increased heart rate
Decreased intestinal movement Increased intestinal movements
Fatigue Hyper irritability
Sleepiness Insomnia
Hair fall Hair fall
Lack of sweat (dry skin) Increased sweating
Weight gain Weight loss
Cold intolerance Heat intolerance
Irregular menses Irregular menses
Labs (↓ T3 ↓ T4 ↑ TSH) Labs (↑T3 ↑T4 ↓ TSH)
Decrease T3 , Decrease T4 Increase TSH Increase T3 , Increase T4 Decrease TSH
Treatment Treatment
Replacement with T4 (±T3) Suppress thyroid gland functioning with:
  Medical treatment or Radioiodine or Surgery

Myths and Facts

Myth: I cannot eat certain foods if I have Hypothyroidism.

Fact: Certain foods like cabbage, cauliflower, turnips, and mustard cause Hypothyroidism when consumed in large quantities and on regular basis. When your thyroid is not functioning optimally, you are already on medication, then there is no need for any further restriction.

Myth: If I’ve gained weight, I need to increase the dosage of Thyroxine for weight loss.

Fact: Hypothyroidism is just one of the causes of weight gain, and is only responsible for weight gain up to a certain limit (3 - 5%). If your Hypothyroidism is well controlled as per the instructions of your doctor, don't overdose yourself. It is not good for your body. You need to talk to your doctor regarding the modification of your diet, your lifestyle, and other factors responsible for your weight gain.

Myth: I can stop taking Thyroxine once I feel well and my reports are normal.

Fact: No. It’s important that you continue to take the medicine regularly despite feeling well. It is because of the external consumption of Thyroxine that reports are normal. Leave the decision of changing and/or stopping therapy to a qualified doctor.

Myth: Taking Thyroxine for a long time can be harmful.

Fact: No. Thyroxine when prescribed in the right dosage for Hypothyroidism, does not cause any ill effects. It's a natural hormone.

Myth: Once I've begun taking Thyroxine, I need to take it for a long time.

Fact: The duration of the therapy depends on the cause of Hypothyroidism. In case of autoimmune medicated Hypothyroidism, Thyroxine needs to be consumed for a long time.

Myth: If I have Hypothyroidism, I will not ever be able to conceive.

Fact: This is a common misconception. If you neglect treating Hypothyroidism, only then is there a chance of a miscarriage, or the birth of a mentally-challenged baby. People whose Hypothyroidism is well controlled have similar chances of conceiving as those without a thyroid disorder. It is advisable to speak to your endocrinologist on the matter.

Myth: If a mother has Hypothyroidism during pregnancy, her offspring will also have it.

Fact: Certain thyroid disease like Hypothyroidism and Hyperthyroidism are known to run in families. The chance of an offspring developing a thyroid disorder is only marginally more than other people.

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